Re: [Jython-users] Data Conversion: Java --> Python

[Jim A. <ji...@tr...>]

Ron...@Ne... wrote:
> 
> I have a bunch of properties that I get from the system using Java code,
>   since that is what handles properties.  The data I get back is of type
> java.lang.String.  These things are used all over the place.
> 
> Which makes more sense:  write all the code in Java and just drive it
> with Jython, or convert the String data to Python strings?  In the latter
> case, how do I do the conversion?
> 

Of course it depends on your purpose, but I would lean toward putting
the info into Jython.
Here's a cut/paste of some of my code:

  import org.python.util.PythonInterpreter;
  import org.python.core.*;
  ...
    PythonInterpreter python;
    python = new PythonInterpreter();

    python.set("debugLevel", new Integer(debugLevel)
);                        // must pass Object not 'int'
    python.set("amount", new PyFloat( Double.parseDouble( amountString )
) );  // so Jython can do math directly

    ArrayList errorList = new ArrayList();
    python.set("errorList", errorList);  

Note that in the last example, the pointer to the ArrayList is sent to
Jython: in the Jython code it calls other Java code using the same
pointer ('errorList'), and the Java code actually 'add's to the
errorList; i.e. the pointer is just 'passed through' Jython.

This all works great and fast since when it actually runs, Jython code
is just Java Bytecodes !

Your other option is just to call the Java classes to get the properties
from Jython directly. See Bruce Eckel's Jython info below for more info.

-- 
                                 __o
Jim Adrig                      _ \<,_
ji...@tr...          ' `/ ' `
                  ___________ `-'  `-'

Java/Jython intergration: Chapter 9 at:
http://www.bruceeckel.com/TIPatterns/index.html